A typical electronic equipment rack includes a vertically extending frame which supports multiple components. Each component typically includes a housing, and electronic circuitry (e.g., a set of circuit boards, an array of disk drives, etc.) which is contained within that housing. Such an equipment rack is well-suited for supporting a variety of electronic systems such as a general purpose computer system, a data storage system, network equipment, test equipment, power supply equipment, as well as other types of electronic equipment.
In general, component manufacturers for electronic equipment racks design the components such that (i) control and display functions are accessible at the fronts of the components (e.g., keyboards, control buttons, LEDs, CRTs, etc.), and (ii) cables connect to the backs of the components (e.g., power cords, communication lines, etc.). Accordingly, after installation of the components, a user can conveniently operate the components from the front of the equipment rack without disturbing the cables running from the back of the equipment rack. For example, with such a design, the user does not need to worry about tripping over wires or inadvertently disconnecting a cable, etc.
Some component manufacturers provide components having equipment housings with substantially contiguous metal sides and/or backs to decrease the amount of electromagnetic interference (EMI) which emanates from the electronic circuitry during operation. These metal sides and backs function as EMI shields and, without such shielding, the component circuitry would release EMI into the surrounding areas which could affect the operation of other components in the vicinity (e.g., the released EMI could prevent neighboring radio equipment from properly receiving a communications signal, or corrupt network signals traveling through cables adjacent the back of the equipment rack, etc.). Furthermore, particular agencies and committees (e.g., the FCC, ISO, ANSI, etc.) have set rudimentary standards which manufacturers must comply with or attempt to comply with depending upon the circumstances (e.g., depending on the application, location, zoning, etc.).
Some component manufacturers provide components having housings with removal metallic plates on the backs of the housings. The plates are removable to allow technicians to get into the housings, e.g., to probe equipment during operation, to operate special switches, to replace components, etc.
If the components require cables, some manufacturers design their housings with circular or oval-shaped holes in the plates or in the walls of the chassis to enable the technicians to run cables therethrough. Other manufacturers design gaps along the edges of the plates so that the technicians can maneuver the cables through the edge-located gaps when mounting the plates to the housings.